Yes...the 300 win. seater works fine. As far as the grinding, rotating it on a bench grinder works just fine (it is only a neck die, there is a little clearance there).

To clarify my last post, re. modifying the Hornady FL die: I meant I am going to grind off the top of the die (as opposed to the bottom of the neck die), where the neck is sized, as to create a lower body die.